The present invention relates to a technique on a snap tap forming method where a gate valve is fixedly attached preliminarily to a peripheral wall of a water pipe having a duplex pipe structure where a regeneration pipe (repair pipe) is fitted into a deteriorated pipe, a water diverting port is formed by drilling the peripheral wall of the water pipe having a duplex pipe structure by a drill body of the drilling machine which is advanceable and retractable in the inside of a water flow sleeve of the gate valve, and the snap tap equipped with the gate valve is attached to the water diverting port of the water pipe, and a snap tap attaching tool used in the method.
Recently, water leakage troubles have frequently occurred along with the progress of deterioration of water pipe passages. Accordingly, it is necessary to dig out a deteriorated pipe which is an existing water pipe and to replace the deteriorated pipe with a new pipe. However, such an operation requires a large amount of time and a large amount of work cost. Accordingly, a regeneration pipe work method has been adopted where an inner surface of an existing pipe is cleaned, and a new pipe (a regeneration pipe) is fitted into and arranged in the inside of the existing pipe.
In a water pipe having the duplex pipe structure installed by such a regeneration pipe arranging method, there may be a case where it is necessary to perform a work for mounting a snap tap so as to divide water for leading water to other places.
In this case, there has been adopted a snap tap forming method of forming a snap tap equipped with a gate valve by fixedly attaching the gate valve to a peripheral wall of a water pipe and by forming a water diverting port by forming a hole in the peripheral wall of the water pipe having a duplex pipe structure by a drill body of a drilling machine which is advanceable and retractable in the inside of a water flow sleeve of the gate valve.
FIG. 10 is a cross-sectional view of the overall structure of a conventional regenerated water pipe 11 and a snap tap 14 mounted on the water pipe 11 for dividing water from, the water pipe 11.
The water pipe 11 shown in FIG. 10 is constituted of: an existing pipe 12; and a regeneration pipe 13 fitted into the inside of the existing pipe 12 for regenerating the existing pipe 12.
The existing pipe 12 is a cylindrical water pipe installed from the beginning, and is a pipe whose deterioration has progressed with time.
The regeneration pipe 13 (NORDIPIPE) is constituted of a plurality of pipes fitted into the inside of the above-mentioned deteriorated existing pipe 12 with a predetermined length, and the deteriorated existing pipe 12 can be regenerated by arranging such a new regeneration pipe 13 in the inside of the existing pipe 12 by fitting.
In installing a branch flow pipe for dividing water from the water pipe 11 in which the regeneration pipe is fitted by branching, it is necessary to perform a work for mounting the snap tap on a predetermined portion of the water pipe.
In this case, a circular annular saddle which is an integral body preliminarily formed of a semi-annular band 38 and a saddle 30 is mounted on a portion of an outer periphery of the water pipe where the snap tap 14 is to be mounted in a surrounding manner.
As shown in FIG. 10, the saddle 30 includes: a saddle body 31 having a semi-annular cross section; and mounting flange portions 33 for band connecting which are formed on both ends of the saddle body 31. A mounting cylinder 32 to which the snap tap 14 is communicably connected is mounted on a center portion of the saddle body 31 in a projecting manner.
Symbol 34 indicates holts and nuts for integrally connecting both ends of the bands 38 having a semi-annular cross section to the mounting flange portion 33 of the saddle body 31. The circular annular saddle is formed by the saddle body 31 and the band 38.
The mounting cylinder 32 formed on the saddle 30 in a projecting manner is integrally fitted in an end portion of a water diverting port of the snap tap 14.
A gate valve 15 (soft seal gate valve) which is a valve device is mounted on the snap tap 14, and the gate valve 15 performs a valve opening or closing function for leading water divided from the existing pipe 12 and the regeneration pipe 13 to a predetermined place through a water diversion passage.
That is, the gate valve 15 is constituted of: a valve operating member (not shown in the drawing); a valve operating shaft 20; a valve casing 21; and a valve element 22. A middle portion of the water dividing passage can be opened or closed by advancing or retracting the valve element 22 in the vertical direction. Symbol 41 indicates a valve seat.
A rubber packing 23 is fitted on an outer periphery of a water diverting port 62 of the water pipe 11 on which the snap tap is mounted by insertion.
As shown in FIG. 10, a metal sleeve 40 is loosely fitted on an inner peripheral surface of the rubber packing 23, a peripheral end portion of the metal sleeve is bent in a peripheral edge direction by a snap tap attaching tool provided separately thus enlarging the peripheral edge portion of the metal sleeve in a trumpet shape in the inside of the regeneration, pipe 13 of the water pipe.
By mounting the rubber packing 23 and the metal sleeve 40 on the peripheral edge of the water diverting port 62, a water leakage from the water diverting port 62 can be prevented. Further, by interposing the metal sleeve 40 between the regeneration pipe 13 of the water pipe and the water flow sleeve 16 of the gate valve 15, a water guide passage leading to the snap tap from the water pipe 11 is formed.
For example, JP-T-2009-535578 discloses a snap tap forming method where a snap tap is formed by forming a water diverting port in a peripheral wall of a water pipe. That is, the snap tap forming method described in JP-T-2009-535578 is a snap tap forming method applicable to the case where a snap tap is newly mounted on a water pipe in which a regeneration pipe is disposed in the inside of an existing pipe. To be more specific, JP-T-2009-535578 discloses the method where a water diverting port is formed by integrally forming a hole in the regeneration pipe and the existing pipe by a drilling machine mounted on a gate valve, and the snap tap equipped with a gate valve is mounted on the water diverting port.
In mounting the snap tap, an opening portion formed at one end of a metal sleeve is made to project from the inside of the water diverting port of the water pipe, and a distal end portion of the opening of the metal sleeve which projects into the inside of the water pipe is bent by a diameter enlarging head mounted on a distal end of a main shaft of a jig inserted into the inside of the sleeve, a diameter enlarging roller mounted on the diameter enlarging head and the like in an inclined manner such that the distal end portion of the opening of the metal sleeve is folded back on an outer periphery of the metal sleeve, and the distal end portion of the opening of the metal sleeve is caulked to the water diverting port of the water pipe.
In this manner, to enable mounting of the snap tap while ensuring watertight connection between the water pipe and the mounting portion of the snap tap, there has been known the use of the snap tap attaching tool which is, as described above, constituted of: the diameter enlarging head mounted on the distal end of the main shaft; the diameter enlarging roller mounted on the diameter enlarging head and the like in an inclined manner.
With respect to the manner of operating the jig, as described in detail previously, the diameter enlarging roller mounted on the diameter enlarging head formed on the distal end of the main shaft in an inclined manner is brought into contact with the peripheral edge portion of the opening of the metal sleeve while manually adjusting the elevation or lowering of the main shaft and, subsequently, the peripheral edge portion of the opening of the metal sleeve is bent by the diameter enlarging roller arranged on the distal end of the main shaft such that the peripheral edge portion is folded back to the outside by rotating the main shaft (see JP-A-9-273186 and JP-A-11-190457).